The invention concerns a wet/dry vacuum cleaner and in particular a shoe attachment for the intake of a vacuum cleaner which is suitable for picking up dry materials, wet materials and even liquids. The invention is useful for the intake of an upright type electric vacuum cleaner and for the intake nozzle of a cannister type vacuum cleaner.
An electric vacuum cleaner generally includes suction generating apparatus, such as a suction fan, which communicates with an intake orifice. To increase suction force at the intake orifice, the orifice is typically of reduced width across at least one dimension, and the reduced size of the orifice increases the speed of air flow through the orifice.
An electric vacuum cleaner may be of the type where the intake orifice is at the front of the underside of a housing that rides along the surface to be suctioned, or it may be of the type having an intake hose with the intake orifice in the nozzle at the end of the hose. The present invention is useful in conjunction with both types of vacuum cleaners.
Furthermore, some vacuum cleaners are known as wet/dry types, in that they are adapted to suction dry particulate materials, wet or damp materials and even liquids. Dry particulate materials are lighter in weight and thus can be suctioned using a smaller suction force. But wet materials and liquids in particular require a relatively greater suction force to be suctioned. In some circumstances, a vacuum cleaner with an intake suction force only great enough to take in dry particulate materials may not have adequate suction force for taking in wet particulate materials or liquids.
It is known to apply a shoe to the inlet of a vacuum cleaner for various purposes, including reducing the size of the inlet opening when higher suction force is needed, and to remove the shoe to enlarge the inlet opening when lower suction force is needed. See U.S. Pat. Nos. 3,958,298; 2,349,371; 3,871,051; and Application Ser. No. 320,721, filed Nov. 12, 1981, now U.S. Pat. No. 4,413,372, by the inventor hereof, and assigned to the assignee hereof.
To sweep material into the inlet opening of the shoe, a blade supported on the vacuum cleaner or on the shoe, but always a separate element from the shoe, is disposed across the shoe at its inlet and pushes material toward the inlet opening as the shoe is moved. The blade is at the middle of the inlet opening, front-to-back, so that it sweeps material to that side of the inlet opening leading the motion of the blade. The separateness of the blade from the shoe requires separate fabrication of and then securement of the blade to the shoe for enabling the blade to move, and this produces an undesirably complicated shoe.
The blade is known to be attached in the shoe or in the nozzle or intake opening that receives the shoe in various ways. These include a swivel hinge in the shoe on which the blade swivels as the nozzle is moved forward and rearward, the blade being captured in a shaped slot in the shoe to permit the blade to swivel as the nozzle is moved, and a flexible blade which flops back and forth with respect to the rigid nozzle to which the blade is affixed. But all of these blades are separate from the shoe, with the drawbacks noted above.